Spark plug



May 19, 1925. 1,537,938

F.' DuMBovlcH SPARK PLUG Filed May 19, 1924 Il .II

Pat/fented May 19, 1925.

4*UNITED 4s'ra'rlazs FRANK DITMBOVICH, OF DETROIT, MICHIGAN.

SPARK PLUG.

Application tiled May 19, 1924. Serial No. 714,387.

To all whom it may concern:

Be it known that I', FRANK DUMBovICH, a citizen of Austria, residing at Detroit, in the county of V'ayne and State of Michigan, have invented certain new and useful lmprovements in Spark Plugs, of which the following is a specification, reference being had therein to the .aecmnpanying drawings.

T his invention has reference to spark plugs for internal combustion engines and has for its object to minimize the trouble often experienced in the usual it'orm of spark plugs from damage or undesirable variations in the setting otl the tiring or sparking points due to the heat and force of cylinder explosions.

It is also an object to provide an easily constructed form of plug wherein a permanent tiring element is provided together with a removable and renewable element; and it is still -urther an object to provide in such a device, for the adjustment of such renewable element with respect to the firing element.

A still further object is to provide ring elements of said type of robust construction particularly adapted to withstand the force and heat of explosions; and still further objects subsidiary to or resulting from the aforesaid objects or from the construction or operation ot the invention as it may be carried into effect, will become apparent as the said invention is hereinafter further disclosed.

In carrying said invention into eiect I may provide a spark plug shell such as of any well known type having extending from its inner end one or more arms supporting a tiring member, in the trout plate or disk in a plane transverse to the said shell and substantially spaced therefrom. the said disk having sharp projections or points on its inner face and the said Shell being provided with the usual insulator and central insulated conductor` to the inner end of which is secured a second tiring member having arms the extremities ot which terminate at a desirable distance from the points on the inner side of the said plate. This latter tiring member is preferably detachable from the plug either with the said conductor or from the said conductor and adjustable with respect to the said plate whereby the distance between the plate and the adjustable tiring member may be varied to suit the circumstances under which the plug is to be used. All ot which is more particularly described and ascertained hereinafter, by way of example, having reference to the accompanying drawing, wherein-- Figurc 1 is an elevation, with parts broken away and shown in section, of a spark plug embodying the Said invention;

Figure 2 is a fragmentary detail view of the lower parts ot the same, also partly broken away and illustrated'in section at right angles to that in Figure l;

Figure 3 is a sectional plan detaill ot the tiring element;

Figure 4- is a broken perspective view of the tixcd tiring element, and

Figure 5 is a similar view to Figure 2 illustrating a modied form of the invention.

Similar characters of reference indicate similar parts, in the several figures ot' the drawing.

l is the tubular threaded shell of a spark plug enclosing an insulator 2 through the center of which passes a conductor 3, and 4.- is a tiring element in the form of a plate or disk integrally connected to and spaced from the lower open end of the said shell l by arms 5, the spacing of the said tiring member 4t from the end of the shell being sucient to permit of free circulation of gases around the said tiring member when the spark plug is in use.

At the lower extremity of the conductor 3 is secured a second tiring element 6 which is shown as being in the form of a bent strip having a pair ot arms 7 provided at their extremities with late al projections 8, whereby said arms are of anginverted 'T- shaped configuration, the transverse heads ot' which arms lie in approximately parallel relation to the tiring member 4 and may be set at an effective tiring space therefrom whereby sparks mayppass between the said plate and any part ot the inverted 'l' heads of the said tiring member To increase the eiiectiveness of the device I prefer to provide the firing member 4: with a plurality of up 'ardly extending projections or points 9 as indicated in Figures 1, 2 and 3.

ln Figure 5 the lower end of the connector 3 is shown as being threaded and provided with adjustable nuts 10 and 1l between which the tiring member G is secured and by means of which said tiring member may be adjusted4 with respect to the tiring 4member Il, which in this case is shown as having a- Cil lll)

lll

central orifice 12 therein to permit access to the nuts by means of a suitable tool for the purpose of eil'ecting their adjustment.

It will be seen that the said firing member 5 may be readily removed and ,replaced if required, in the case of the arrangement shown in .Figure 5 by its detachment from the end of the conductor 3 and in the case of Figure l by the withdrawal of the conductor from the insulator 2 after its removal from the shell. i

The arrangements described are very simple in construction and capable of being made very rigid to withstand hard usage, the fixed firing member 4 being of a particularly robust nature and acting as a. protecting shield for the firing element 6 whereby the force of explosion does not tend. to bend or otherwise alter the spaced adjustment of the two firing members.

This invention may be developed within the scope of the following claims without departing from the essential features of the said invention and it is desired that the specification and drawing -be read as being merely illustrative and not in a limiting sense except as necessitated by the prior art.

1. In a device of the class described, a firing member in the form of a plate, and a further firing member having downwardly projecting arms provided with lateral projections extending approximately parallel to said plate.

2. In a device of the class described, a firing member in the form of a plate provided with upwardly projecting points, and a further firing member having downwardly projecting arms provided with lateral projections at their extremities extending approximately parallel to said plate.

In a device of the class described, a ring member in the form of a plate provided with upwardly projecting points, and a further firing member having downwardly projecting arms provided with lateral projections at their extremities terminating in proximity to the points on said plate.

4. In a device of the class described, a

she-ll, an insulator therein, a conductor passing through said insulator, a firing member on the inner end of said conducto-r and a further firing member spaced from the i'nner end of said shell and extending protectively over and in spaced relation to said first mentioned firing member.

5. In a device of the class described, a firing member in the form of a plate, and a further firing member having inverted T- shaped arms the heads of which terminate in proximity to said plate.

In tesrtimony whereof I aflix my signature in prese ce of two witnesses.

FRANK DUMBOVICH.

Witnesses J. L. LIGHTFoo'r, ANNA M. Donn. 

